156 METHOD OF COMPLEMENT FIXATION 



stead of the extract of tuberculous organs. Thus, the latter contained 

 tuberculin while the sera of the tuberculin- treated individuals contained 

 amboceptors designated by Wassermann and Bruck as "antituberculin." 

 The name antituberculin has not been a well chosen one, because it creates 

 the impression among many as being an antitoxin. It is better to speak of 

 it as antituberculin amboceptors. 



Since, according to Wassermann and Bruck these antituberculin ambo- 

 ceptors were not supposed to be formed spontaneously in tuberculous indi- 

 viduals, but only in those treated with tuberculin their demonstration 

 could be of no apparent diagnostic value. On the other hand, their exist- 

 ence greatly furthered the understanding of Koch's tuberculin reaction, as 

 most tuberculous individuals who had antituberculin amboceptors in their 

 serum did not respond to the subcutaneous injection of tuberculin. 



Wassermann and Bruck, moreover, showed that a mixture of tuberculin 

 with an extract from tuberculous organs bound complement. From this 

 they concluded that the extract likewise contains antituberculin ambo- 

 ceptors. Thus reasoning they developed their tuberculin theory. 



The difference in the reaction observed in a normal and tuberculous 

 Tuberculin individual after inoculation with tuberculin, can be fully explained by the 

 Theory of presence of antituberculin amboceptors in the tuberculous focus. By 

 Wassermann virtue of their specific affinity, the amboceptors attract the injected 

 and Bruck. tuberculin toward them. The tuberculin and antituberculin unite, 

 and absorb the complement from the circulating blood stream, since the 

 complementophile group of the amboceptor is free and unbound. By virtue of the 

 fresh complement which is an actively lytic ferment, and the attracted leucocytes, a 

 partial destruction and casting off of the tuberculous focus results. Upon this depends 

 the therapeutic effect of the tuberculin. During a prolonged treatment with tuber- 

 culin, the body produces an excess of antituberculin amboceptors so that finally some 

 appear free within the blood serum. When this is the case the tuberculous organism 

 loses its power to react toward tuberculin, as the latter is neutralized in the blood- 

 stream at a point away from the local focus. No therapeutic effect is any longer 

 obtained from the tuberculin injections, so that they can, for a time, be suspended. 

 The aim of tuberculin therapy should be to work with small doses so that only a focal 

 reaction is obtained and the hyperproduction of antituberculin amboceptors be post- 

 poned as long as possible. 



Numerous exceptions were at once taken to this theory and its experimental data, 

 the most important of which can here be mentioned. 



" Summier- 



d" (E ^ 6 ^ an( * Nakayama disagreed with the proof of the existence of "anti- 

 tuberculin" in the organ extracts, on the basis that Wassermann had 



overlooked the effect of a summation of antigen. This is best explained 

 taken on .,.. 



as follows: Complement is bound not only by antigen + amboceptor, 



but also by large doses of antigen itself dependent upon the normally 

 . present amboceptors existing in the serum employed for complement 



Antigen.) 



